From 10331795fb7991a39ebd0330fdb074cbd81fef48 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Dec 2021 15:24:51 -0500 Subject: pagevec: Add folio_batch The folio_batch is the same as the pagevec, except that it is typed to contain folios and not pages. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: William Kucharski --- include/linux/pagevec.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'include/linux/pagevec.h') diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index 7f3f19065a9f..c3fa616d7ae7 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -15,8 +15,10 @@ #define PAGEVEC_SIZE 15 struct page; +struct folio; struct address_space; +/* Layout must match folio_batch */ struct pagevec { unsigned char nr; bool percpu_pvec_drained; @@ -81,4 +83,71 @@ static inline void pagevec_release(struct pagevec *pvec) __pagevec_release(pvec); } +/** + * struct folio_batch - A collection of folios. + * + * The folio_batch is used to amortise the cost of retrieving and + * operating on a set of folios. The order of folios in the batch may be + * significant (eg delete_from_page_cache_batch()). Some users of the + * folio_batch store "exceptional" entries in it which can be removed + * by calling folio_batch_remove_exceptionals(). + */ +struct folio_batch { + unsigned char nr; + bool percpu_pvec_drained; + struct folio *folios[PAGEVEC_SIZE]; +}; + +/* Layout must match pagevec */ +static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch)); +static_assert(offsetof(struct pagevec, pages) == + offsetof(struct folio_batch, folios)); + +/** + * folio_batch_init() - Initialise a batch of folios + * @fbatch: The folio batch. + * + * A freshly initialised folio_batch contains zero folios. + */ +static inline void folio_batch_init(struct folio_batch *fbatch) +{ + fbatch->nr = 0; +} + +static inline unsigned int folio_batch_count(struct folio_batch *fbatch) +{ + return fbatch->nr; +} + +static inline unsigned int fbatch_space(struct folio_batch *fbatch) +{ + return PAGEVEC_SIZE - fbatch->nr; +} + +/** + * folio_batch_add() - Add a folio to a batch. + * @fbatch: The folio batch. + * @folio: The folio to add. + * + * The folio is added to the end of the batch. + * The batch must have previously been initialised using folio_batch_init(). + * + * Return: The number of slots still available. + */ +static inline unsigned folio_batch_add(struct folio_batch *fbatch, + struct folio *folio) +{ + fbatch->folios[fbatch->nr++] = folio; + return fbatch_space(fbatch); +} + +static inline void folio_batch_release(struct folio_batch *fbatch) +{ + pagevec_release((struct pagevec *)fbatch); +} + +static inline void folio_batch_remove_exceptionals(struct folio_batch *fbatch) +{ + pagevec_remove_exceptionals((struct pagevec *)fbatch); +} #endif /* _LINUX_PAGEVEC_H */ -- cgit v1.2.3 From 1613fac9aaf840af76faa747ea428a714af98dbd Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Tue, 7 Dec 2021 14:28:49 -0500 Subject: mm: Remove pagevec_remove_exceptionals() All of its callers now call folio_batch_remove_exceptionals(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: William Kucharski --- include/linux/pagevec.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'include/linux/pagevec.h') diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index c3fa616d7ae7..dda8d5868c81 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -27,7 +27,6 @@ struct pagevec { void __pagevec_release(struct pagevec *pvec); void __pagevec_lru_add(struct pagevec *pvec); -void pagevec_remove_exceptionals(struct pagevec *pvec); unsigned pagevec_lookup_range(struct pagevec *pvec, struct address_space *mapping, pgoff_t *start, pgoff_t end); @@ -146,8 +145,5 @@ static inline void folio_batch_release(struct folio_batch *fbatch) pagevec_release((struct pagevec *)fbatch); } -static inline void folio_batch_remove_exceptionals(struct folio_batch *fbatch) -{ - pagevec_remove_exceptionals((struct pagevec *)fbatch); -} +void folio_batch_remove_exceptionals(struct folio_batch *fbatch); #endif /* _LINUX_PAGEVEC_H */ -- cgit v1.2.3 From 6840f9094f2bd788a316d8cb0a4e42538d3e47dd Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 13 Jan 2022 16:44:19 -0500 Subject: pagevec: Initialise folio_batch->percpu_pvec_drained When UBSAN is enabled, it reports an invalid value in __pagevec_release() when accessing pvec->percpu_pvec_drained, which is simply whatever garbage was on the stack. Initialise it when initialising the rest of the folio_batch. Fixes: 10331795fb79 ("pagevec: Add folio_batch") Reported-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/pagevec.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/pagevec.h') diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index dda8d5868c81..67b1246f136b 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -111,6 +111,7 @@ static_assert(offsetof(struct pagevec, pages) == static inline void folio_batch_init(struct folio_batch *fbatch) { fbatch->nr = 0; + fbatch->percpu_pvec_drained = false; } static inline unsigned int folio_batch_count(struct folio_batch *fbatch) -- cgit v1.2.3